3.1 The Sb/I2 Reaction

Samples of Sb and I2 (Sb is in excess) are added to toluene
inside the reflux apparatus.

The solution is filtered while still hot.

After refluxing, the solution is poured into the beaker and immersed in an ice bath.

The solution is then filtered after it is cooled.

Observations:

After the solution has been cooled, SbI3 product is
collected.

Explanation:

2 Sb (s) + 3 I2 (s) --> 2 SbI3 (s)

SbI3 is soluble in toluene at reflux temperature, but Sb
is not. The excess Sb is removed by filtering the solution while the it is still
hot. When SbI3 is cooled it becomes insoluable and the product can be
collected by filtering the solution again.

The reaction has been used in the past to expose students to the
rudiments of stoichiometry.